Torsion damping device, notably for motor vehicles

ABSTRACT

A torsion damping device having two coaxial parts (12, 3) mounted so as to move angularly with respect to each other counter to elastic member (7), including members (71, 72, 73) acting between radial lugs (55, 65) offset circumferentially and belonging to two phasing washers (5, 6). The phasing washers (5, 6) are mounted in reverse orientations and concentrically, the outer washer surrounding the inner washer. The inner washer (5) is pivotally mounted on a first one (3) of the coaxial parts (3, 12), while the outer washer (6) is pivotally mounted on the first or the second of the coaxial parts (3, 12).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns torsion damping devices, notably formotor vehicles, of the type having one input part and one output partcoupled elastically by means of two phasing washers each mounted freelyon one of the parts.

2. Description of the Prior Art

Such a damping device is described, for example, in the document U.S.Pat. No. 4,139,995, and therefore has two coaxial parts mounted so as tomove angularly with respect to each other counter to elastic means withcircumferential action, comprising elastic members acting between lugsoffset circumferentially and belonging to two phasing washers which arethe image of each other.

In this document, the input part is formed by a housing in two parts andthe output part by a hub fluted on the inside, and the phasing washersare mounted so as to rotate with respect to the two coaxial parts.

More precisely, the phasing washers are pivotally mounted on the hub andeach have radial arms for the bearing of elastic members withcircumferential action.

These washers are offset circumferentially so that three sets of springsare mounted in series between two consecutive bearings borne by thehousing.

One of the sets of springs bears on the bearing of the housing and on alug of one of the phasing washers, while another one of the sets ofsprings is interposed circumferentially between the aforementionedphasing lug and a lug of the second phasing washer. Finally, the thirdset of springs is mounted between the bearing of the housing and the lugof the second phasing washer.

In practice, the shape of these phasing washers is tortuous, since theyare mounted on each side of a web, of a single piece with the hub.

The inner periphery of a phasing washer is thus axially offset withrespect to its outer periphery.

The object of the present invention is to overcome this drawback andtherefore create a torsion damping device with simplified phasingwashers.

SUMMARY OF THE INVENTION

According to the invention, a torsion damping device of theaforementioned type is characterised in that the two phasing washers aremounted in the same plane, in reverse orientations and concentrically,one of the washers, referred to as the outer washer, surrounding theother washer, referred to as the inner washer, in that the lugs of theinner washer are directed in a direction opposite to the axis of theassembly, while the lugs of the outer washer are directed towards theaxis of the assembly, and in that the inner washer is pivotally mountedon a first one of the said coaxial parts of the torsion damping device,while the outer washer is pivotally mounted on the said first or thesaid second part of the torsion damping device.

By means of the invention, the phasing washers can be simple in shape.These phasing washers can be manufactured by cutting out on a press, thematerial for the inner phasing washer being taken from the waste fromthe outer phasing washer.

In one embodiment, the outer phasing washer is pivotally mounted on thelugs of the inner phasing washer. In another embodiment, the outerphasing washer is pivotally mounted on lugs belonging to the second ofthe said coaxial parts, the inner phasing washer being pivotally mountedon the said first of the coaxial parts.

In one embodiment, the second of the parts of the torsion damping devicehas lugs for the bearing of the elastic members in question, the saidlugs being cut out for the passage of fingers belonging to the second ofthe coaxial parts of the torsion damping device.

These fingers are suitable for each acting on a dish interposed betweenthe circumferential end of the spring or springs in question and the lugassociated with the second coaxial part of the torsion damping device inquestion.

By virtue of this arrangement, it is possible to obtain a torsionaldamper with a large angular movement.

This torsion damping device can belong to a friction disc, as mentionedin the document U.S. Pat. No. 4,139,995. As a variant, this torsiondamping device can belong to a locking clutch mounted between theturbine and the housing of a hydrokinetic coupling apparatus.

The description that follows illustrates the invention in relation tothe accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in axial section of the hydrokinetic coupling apparatuswithout the locking clutch in the top part of this figure and with onlythe locking clutch piston in the bottom part of this figure;

FIG. 2 is a view in axial section along the line 2--2 in FIG. 3 of thehydrokinetic device with its locking clutch;

FIG. 3 is a view in cross section along the line 3--3 in FIG. 2;

FIG. 4 is a view to an enlarged scale of the bottom part of FIG. 2;

FIG. 5 is a view similar to FIG. 4, for a variant embodiment;

FIG. 6 is a partial view to a larger scale of part of FIG. 3;

FIG. 7 is a half-view in axial section similar to FIG. 2, for anotherexample embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated by the figures, the locking clutch 10 using a torsiondamping device 4 is intended for equipping a hydrokinetic couplingapparatus 11, including a torque converter or a coupling, which isitself designed to equip a motor vehicle.

Such an apparatus is described in the patent U.S. Pat. No. 4,976,656, towhich reference can be made, and this is the reason why, for the sake ofsimplicity, only the first part of the housing 12 and turbine wheel 14have been depicted in FIG. 1, the impeller wheel and the reactor wheelnot being visible.

For information, it should be stated that this apparatus 11 includes, ina sealed housing 12 capable of being rotatably connected to thecrankshaft of the internal combustion engine, at least one impellerwheel fixed to the other part of the housing, in the form of ahalf-shell, and a turbine wheel 14, which is capable of being rotatablyconnected to the gearbox input shaft. In this case the apparatus 11includes, in order to form a torque converter, also a reactor wheelcarried by a fixed sleeve surrounding the said input shaft with theinterposition of a free wheel.

The locking clutch 10 acts, in a manner known per se, axially betweenthe turbine wheel 14 and housing 12, annular in shape, at the outerperiphery of the latter.

It includes a piston 2 capable of coming into contact with a mass 3 inorder to establish a direct connection between the turbine wheel 14 andhousing 12.

In a manner known per se, the turbine wheel and impeller wheel includeblades so that the turbine wheel 14 is rotated by the impeller wheelfixed to the housing 12 by means of the circulation of the oil containedin the housing 12.

The locking clutch 10 acts in a manner known per se after the start-upof the motor vehicle in order to avoid slip phenomena and losses ofenergy.

The turbine wheel 14 is fixed, in this case by welding or as a variantby riveting, to a turbine hub 13 fluted internally for rotatoryconnection with the aforesaid input shaft of the gearbox.

This hub 13, in this case metallic, has at its outer periphery anexternally fluted annulus 15 of axial orientation.

The piston 2 is in this case fixed by welding, or as a variant byriveting, to an internally fluted bush 25 in order to come into anengagement in a complementary manner with the flutes on the annulus 15.

Thus the housing 12 forms the driving element and the hub 13 the drivenelement of the hydrokinetic coupling apparatus 11.

The housing 12 is therefore capable of being rotatably locked on thedriving shaft (the drive shaft of the vehicle), whilst the turbine wheel14 is capable of being rotatably locked on a driven shaft (the gearboxinput shaft).

The housing 12 also forms the input element of the locking clutch 10 andof the torsion damper 4, whilst the piston 2 forms the output element ofthe locking clutch 10 whilst being capable of being coupled to the hub13.

The piston 2, of transverse orientation overall, is thus, as describedpreviously, rotatably connected to the turbine wheel 14 (in this casevia the hub 13), whilst being mounted so as to be axially mobilevis-a-vis the turbine wheel 14.

A sealing device 16 is located between the front face of the bush 25 andthe internal bore of the annulus 15. This device includes an annularpart with an L-shaped cross section welded on the one hand to thetransverse plate, which the bush 25 has at its axial end furthest fromthe wheel 14 for fixing the piston 2 by welding, and on the other handto a ring interposed between the internal periphery of the annulus 15and the outer periphery of the tubular axial part of the aforementionedannular piece. A sealing joint is provided between the said ring and theannulus 15.

In addition the housing 12 carries centrally a nose 17, tubular inshape, forming a centring ring. This nose 17, of axial orientation, isdirected towards the turbine wheel 14. It is attached by fixing to thehousing 12, in this case by welding, for example by welding of the lasertype, with the formation of a bead.

More precisely the nose 17 is attached centrally to the wall 28,transverse overall, which the housing 12 has at its front.

The nose 17 surrounds the front end of the hub 13 and a thrust ring 18interposed axially between the free end of the hub 13 and the housing.This ring 18, in this case made of friction material, has, in a mannerknown per se, transverse channels (not visible) for establishingcommunication between the inside and outside of the hub 13.

For information, it should be stated that the input shaft of the gearboxis hollowed out internally so that the fluid, in this case oil, cancirculate through the ring 18 in order to operate the piston 2.

This ring 18 has a retaining insert fixed to the housing, in this caseby spot welding.

According to one characteristic the piston 2 is interposed axiallybetween the turbine wheel 14 and a mass 3 pivotally mounted on the nose17.

The mass 3 carries at its outer periphery an annular projection 31 oftransverse orientation offering a contact surface 32 for the piston 2opposite a transversely oriented counter-surface 22 of the piston 2.

In this case, when the clutch 10 is engaged, the piston 2 bearsindirectly through its counter-surface 22 on the surface 32, a frictionlining 40 being interposed axially between the surface 32 and the piston2. This lining 40 is in this case bonded to the surface 32, but theconverse is possible, since the lining 40 can be bonded to the piston 2provided at its outer periphery with an axially oriented annularshoulder 21 in order to stiffen it.

It is between the inner periphery of the axially oriented annularshoulder 19 which the housing 12 has at its outer periphery, and theouter periphery of the turbine wheel 14, that the surface 32 is located.To this end, the projection 31 is connected by an inclined part 33 tothe main part of the mass 3 forming, according to one characteristic ofthe invention, the counter-piston of the clutch 10.

Likewise an inclined part connects the counter-surface 22 of the piston2, in this case made from pressed sheet metal, to the transverselyoriented main part thereof.

Thus the surface 32 and counter-surface 22 are axially offset in thedirection of the turbine wheel 14, in this case by means of the inclinedparts 23, 33 making it possible to fit the shape of the wheel 14optimally and therefore to reduce the axial dimension.

According to one characteristic the inclined part 33 offers a bearingsurface for a phasing washer 5 with a cross section of trapezoidal shapeoverall.

More precisely it is the face 34 turned in the opposite direction to thepiston 2 and the wheel 14 of the inclined part 33, tapered in shape,which forms the said bearing surface. This face 34 is connected to theaxially oriented annular face 35, which the main part of the mass 3 hasat its outer periphery.

According to one characteristic, the mass 3 has, from place to place,radial projections 9. In this case, three projections 9 are provided.These projections 9 are wedge-shaped in cross section (FIG. 2) and offeran inclined bearing face 36 opposite the face 34.

The face 36 is inclined in the opposite direction with respect to theface 34.

According to one characteristic the projections 36 extend at the levelof the free end of the face 35 so that a trapezoid-shaped groove withtwo inclined faces 36, 34 and a bottom 35 is formed locally.

The distance between the inclined faces 34, 36 is determined by thewidth of the phasing washer 5 so that the latter can be housed in thedivided groove and come to bear, with assembly tolerance, on the faces36, 34. An annular radial clearance exists between the external face 35and the washer 5.

Thus the washer 5, referred to for convenience as the inner phasingwasher, is locked axially and radially by the faces 36, 34 and the mass3 thus forms a pulley for the washer 5.

In order to be able to mount the washer 5 in the grooves in the mass 3,according to one characteristic, the said washer 5 has locally passages51 into which the projections 9 are able to enter. Circumferentiallythese projections 9 have in this case a triangular shape overall (FIG.3) and the same applies to the passages 51 formed therefore by means ofa projecting deformation 52 in the direction opposite to the axis of theassembly, the said deformation 52 being triangular in shape.

Thus the mounting of the washer 5 in the grooves is of the bayonet typewith, initially, axial engagement of the deformations 52 over theprojections 9 and then rotation with engagement of the washer 5 in thegrooves and axial locking thereof.

The mass 3 is elastically coupled to the housing 12, in this case by thetorsion damping device 4 acting at the outer periphery of the mass 3.More precisely this device acts on the one hand radially between theinner periphery of the outer shoulder 19 of the housing 12 and the face35 and, on the other hand, axially between the transverse part 28 of thehousing 12, in this case made from pressed sheet metal, and theprojection 31 on the mass 3, in this case made of steel or, as avariant, cast iron.

This device includes, according to the invention, another phasing washer6, referred to as an outer phasing washer, in this case pivotallymounted on the outer periphery of the first phasing washer 5.

In this case, these washers 5, 6 are made of metal, and are produced bycutting out on a press. These phasing washers 5, 6 are mounted inreverse orientations and concentrically, the material of the innerwasher 5 being taken economically from the waste material of the outerwasher 6 surrounding the washer 5.

The phasing washers 5, 6 are thus mounted in the same plane.

These washers 5, 6 are in the image of each other and each have radiallugs respectively 55, 65, each with fingers respectively 56, 66extending circumferentially on each side of the lugs 55, 65 for centringof the circumferential-action elastic means 7 described below.

The lugs 55 on the washer 5 are directed radially in the directionopposite to the axis of the assembly, whilst the lugs 65 on the washer 6are directed towards the axis of the assembly.

These lugs 55, 65 have an overall trapezoidal shape, the free end of thelugs 65 extending at a distance from the washer 5, whilst the top edge,with a greater circumferential width, of the lugs 55 serves, accordingto one characteristic, for centring the outer washer 6.

This washer 6 is thus, according to one characteristic, pivotallymounted on the outer periphery of the lugs 55.

Naturally the height of the lugs 65 is such that it does not interferewith the deformations 52, and the number of lugs 55, 65 depends on theapplications.

In this case three lugs 55, 65 are provided. The lugs 55 are distributedevenly at 120° with respect to each other and extend from the top of thedeformations 52.

The lugs 65 are also distributed evenly at 120° with respect to eachother.

The housing 12 carries from place to place bearing lugs 95, whilst themass 3 carries fingers 85, circumferentially oblong in shape.

Three lugs 95 distributed evenly at 120° with respect to each other andthree fingers 85 also distributed at 120° with respect to each other areprovided.

The fingers 85, cast in one piece with the mass 3, extend axially andthe same applies to the lugs 95 attached by welding to the housing 12(on the transverse wall 28 thereof). These lugs 95 offer transversely alarge bearing surface (FIGS. 4 and 5).

In the idle state of the torsion damping device the fingers 85 enter acircumferential cutout 97 (FIGS. 4 and 6) on the bearing lugs 95.

As can be seen in FIG. 3, in the idle state of the torsion damperbetween two consecutive lugs 95 there are found successively a lug 65and then a lug 55, the circumferential offset between two consecutivelugs 55, 65, 95 being 40° overall.

In this position, the projections 9 are in a median position withrespect to the lugs 55, so that the washer 5 is not able to escapeduring the relative angular movement between the mass 3 and the washer5.

Thus the lugs 65 on the outer washer 6 are offset circumferentially withrespect to the lugs 55 on the inner washer 5, and in this case threesets of two concentric elastic members 73, 72, 71 are provided, actingcircumferentially between two consecutive lugs 95, being mountedradially between the two washers 5, 6.

These elastic members belong to the aforesaid circumferential-actionelastic means 7 and in this case consist of concentric helical springsof the same stiffness.

By virtue of the formation of the lugs 95 and fingers 85, it is possiblethus to have three groups of three sets of elastic members acting inparallel, the three sets of elastic members acting in series between twoconsecutive bearing lugs 95.

According to another characteristic, the last of the elastic members 73bears on a support dish 96, in this case metallic (FIG. 6).

This dish 96 is curved centrally, in this case in a semi-circularfashion, in order to cooperate with one of the circumferential ends ofthe fingers 85, the said end being rounded for this purpose in order toenter the curved part of the dish 96.

In the idle position of the damper 4, the fingers 85 bear on the dishes96 (FIG. 6).

Naturally a circumferential clearance may exist since, in theaforementioned idle position, the dishes 96 are in abutment on thelateral edges of the lugs 95 (FIG. 6).

The fingers 85, arched in shape (FIG. 6), are mounted telescopicallyinside the lugs 95 by virtue of the hollowed-out passages 97 therein.

Thus the phasing washers 5, 6 are mounted so as to rotate with respectto the two coaxial parts 12, 3, and when there is a relative movementbetween the mass 3 and the housing 12, the fingers 85 are allowed to acton the dishes 96 in question and to compress the elastic members 73,which bear on the lugs 65 which then move, causing a compression of themembers 72 bearing on the lugs 55 which move in order to compress thesprings 71 bearing on the lugs 95.

By virtue of this arrangement, it is possible to obtain large angularmovements between the fingers 85 and the lugs 95. In this case, all themembers 71, 72, 73 have the same stiffness but this is not necessarilythe case, for example the members 72 may have a greater stiffness thanthe members 73, which may have a greater stiffness than the members 71,chosen for example to filter the vibrations in the idling range of thevehicle engine.

It is possible thus to obtain a torsion damping device with multiplegradients and variable stiffness.

Naturally this depends on the applications and notably on the torque tobe transmitted.

It will be noted that the inner periphery of the lugs 95 is profiled soas to hold the dishes 96 (FIG. 6). Thus the inner edge of the lugs 95 isbroadened.

It will also be noted (FIG. 5) that the outer washer 6 is locked axiallyby means of a rectangular cut-out 98, which the welded lugs 95 have attheir outer periphery 80.

In FIG. 4 the washer 6 is locked axially in a single direction by meansof a shoulder 99.

In some cases, the elastic means 7 effect such a locking by themselvesalone because the lugs 65 come into engagement, through their fingers66, with the springs 72, 73, themselves in engagement with the lugs 95and 55.

In FIG. 2, the mass 3 is pivotally mounted on the tubular nose 17 fixedto the housing 12 by means of a plain bearing 41.

It will be noted that a sealing joint is provided between the innerperiphery of the mass 3 and the outer periphery of the bearing 41 inthis case fixed to the nose 17.

A friction washer 44 is interposed axially between the wall 28 of thehousing 12 and the mass 3, whilst a friction washer 45 acts on the otherface of the mass 3.

This washer is held by an application washer 43 locked axially by acirclip 42 mounted in a groove, which the nose 17 has at its free end.

According to another characteristic a variable hysteresis device 80 actsbetween the front wall 28 of the housing 12 and the mass 3.

This device includes an axially acting elastic washer 83 of theBelleville washer type (or a crinkle washer as a variant) and anapplication washer 84 bearing on its face directed towards the wall 28 afriction lining in this case fixed by bonding to the washer 84.

Naturally the friction washer can be bonded against the wall 28.

The washers 83, 84 are mounted in a hollow 81 which the mass 3 has forthis purpose.

As can be seen in FIG. 2, the washer 83 bears between the bottom of thehollow 81 to act on the washer 84 and force the said washer 84 in thedirection of the face 28 in order to grip the friction lining of thewasher 84 in contact with the wall 28.

Thus the mass 3 is pivotally mounted at its inner periphery on thehousing 12 by means of an annular bearing 41, 44, 45 in a U shapeoverall.

The piston 2 delimits, in a manner known per se, two chambers.

When the vehicle starts up, the piston 2 is at a distance from the face32 and mass 3. A hydraulic pressure is then established in the chamberdelimited by the piston 2, mass 3 and hub 13.

This chamber is then fed from transverse channels in the ring 18.

The locking clutch 10 is then disengaged and the impeller wheel can thendrive the turbine wheel 14 and hub 13 by means of the circulation of thefluid contained in the housing 12.

In order to avoid slip phenomena and energy losses, once the turbinewheel 14 is being driven, the hydraulic pressures in the two controlchambers delimited by the piston 2 are reversed.

The piston 2 is then allowed to move up to the lining 40 and then clampthe said lining 40.

During this phase, the elastic washer of the hysteresis device 80 isrelieved.

It will be noted that here the application washer 84 is locked withrespect to rotation by means of a pin 82 located at the level of thehollow 81.

Naturally a circumferential clearance can be provided, the washer 84acting in a deferred manner.

To this end, the washer 84 bears at its inner periphery at least oneaxially oriented lug able to come into engagement with the pin 82.

Naturally, as a variant (FIG. 7), the mass 3 can have at least onecut-out 181 in the form of a mortice for the entry, optionally withcircumferential clearance, of a lug 182 in the form of a tenon which theapplication washer 184 has at its inner periphery.

The Belleville washer 183 is then interposed axially between the mass 3and the application washer 184, being centred by the lug 182.

It will be noted that, in this figure, the washers 44 and 43 have beenomitted and that the mass 3 is able to move axially.

By virtue of all these arrangements, a locking clutch is obtainedhaving, at the level of the hub 13, a very low inertia, principally thatof the piston, when it is in the disengaged position, and with a highinertia, due to a great extent to the heavy mass 3, when it is engaged(with the lining 40 gripped between the surface 32 and counter-surface22).

This high inertia makes it possible to reduce the resonant frequency ofthe kinematic chain extending from the vehicle engine to the gearbox viathe apparatus 11.

This resonant frequency is thus very low. Thus, when the vehicle istravelling, this resonant frequency is significantly exceeded, which isfavourable for the comfort of the user.

It will be noted that, when the piston 2 is engaged, in a first phase,the friction due to the hysteresis 80 is great and then diminishes asthe lining 40, optionally segmented, is gripped, the hydraulic pressureacting against the force developed by the elastic washer 83, 183. Whenthe clutch is disengaged the friction forces increase.

Thus, when the vehicle starts off, when passing through the resonantfrequency, there is a high level of friction between the housing 12 andwasher 84 (the mass 3 then moving with respect to the housing 12) inorder better to damp the vibrations, and then this friction diminishes.

It will be noted that the torsion damper 4 also makes it possible toattenuate vibrations, and that the embodiment in FIG. 7 is preferablesince the mass 3 is able to move axially.

Naturally it is possible to remove the washer 44 in FIG. 2. In all casesthe circlip 42 limits the axial movement of the mass 3 in order toprevent notably a licking of the lining 40 when the clutch 10 isdisengaged.

Because of this possibility of movement, in normal running (with clutch10 engaged), low friction is obtained between the wall 28 of the housing12 and the mass 3 since the washer 83, 183 is relieved. The hysteresisdevice 80 is thus variable.

As will have been understood, the input part of the locking clutch is intwo coaxial parts, namely the mass 3 and the housing 12, and the torsiondamper 4 has two coaxial parts 12, 3 mounted so as to be able to moveangularly with respect to each other within the limits of a givenangular movement.

A very high level of comfort is thus obtained for the user.

Of course, the present invention is not limited to the exampleembodiment described. In particular, the mass 3 can be pivotally mountedon the nose 17 by means of a ball bearing with one or more rows ofballs.

The springs 71, 72, 73 may have only one spring.

As a variant, the hydrokinetic coupling apparatus 11 may include acoupling which has no reactor wheel.

In all cases the housing 12 constitutes here the driving element of thehydrokinetic apparatus and also the input element of the torsion dampingdevice, the mass 3 constituting the output part of the said torsiondamper.

The piston 2 constitutes the output element of the locking clutch lockedwith respect to rotation with axial mobility on the driven element ofthe hydrokinetic coupling apparatus.

As a variant the piston 3 can be pivotally mounted on the hub 13 whilstbeing coupled directly to the turbine wheel 14 by tangential tongues.

The hub 13 then has no fluting at its outer periphery.

It will also be appreciated that the response time for engaging anddisengaging the clutch 10 are very short because of the low inertia ofthe piston 2 and because the gear wheels in the gearbox are lightlystressed when the clutch 10 is released because of the low inertia ofthe piston 2.

Naturally the washer 6 can be centred by the lugs 95.

As will have been understood, and as emerges clearly from thedescription, the inner phasing washer 5 is pivotally mounted freely withrespect to the mass 3, while the second phasing washer is pivotallymounted freely either with respect to the lugs 55 of the washer 5 andtherefore to the mass 3 or to the lugs 95 belonging to the second partof the torsion damper, the mass 3 constituting the first part of thetorsion damper.

Of course, the torsion damper can belong to a torsion damping device asdescribed in the document U.S. Pat. No. 4,139,995.

In this case, the mass 3 is replaced by a hub fluted on the inside inorder to be locked with respect to rotation in relation to a drivenshaft.

This hub is then tubular in shape, so that the inner phasing washer ispivotally mounted freely on the outer periphery of the hub.

On the outer periphery of the hub it is possible to form grooves withinclined faces 34, 36, as described previously.

The outer phasing washer is then pivotally mounted freely either withrespect to the lugs of the inner phasing washer or the spacing washerprovided between the two parts of the housing forming the first part ofthe torsion damper, the said housing carrying a friction disc whosefriction linings are suitable for being clamped between the pressure andreaction plates of a clutch.

As a variant, as described in FIG. 12 of the document U.S. Pat. No.4,139,995, the housing can be fixed rigidly to the reaction plate.

As a variant, the torsion damping device can consist of a double dampingflywheel with a plate fixed to the crankshaft and the mass 3 pivotallymounted on the nose 17 of the plate. The mass 3 then forms the reactionplate of a friction disc clutch.

Of course, in any case, dishes 96 can be provided at eachcircumferential end of the springs 71, 72, 73.

As a variant, the structures can be reversed. Thus the inner phasingwasher 5 can have at its inner periphery lugs directed radially towardsthe axis of the assembly and the mass 3 the passages.

For example the mass 3 has a complementary groove hollowed in its face33. This groove is interrupted locally (the front edge of this directedtowards the housing 12) for passage of the inner lugs of the washer 5.These lugs then advantageously have in cross section a shapecomplementary to that of the groove in order to be engaged therein.

Thus the washer 5 can have, for example, three inner lugs evenlydistributed circumferentially and the mass 3 three correspondingcut-outs. The lugs are then engaged axially in the cut-outs, and then arotation and therefore a mounting of the bayonet type is effected.

Thus the centring washer 5 has projections from place to place, whilstthe mass 3 has locally passages into which the projections are able toenter, so that the mounting of the inner washer on the mass 3 is of thebayonet type. The groove being for example trapezoidal in shape, as inthe previous figures, the first coaxial part (the mass 3) therefore hasat its outer periphery a first bearing face opposite another bearingface cut out for the lugs of the inner washer to pass, so that a groove,in this case trapezoidal, is formed for the housing of the inner washer,locked axially and radially by its inner lugs, trapezoidal in crosssection, complementary to that of the groove.

Naturally the groove can be rectangular in cross section, just like thecomplementary lugs.

We claim:
 1. A torsion damping device comprising: a first and secondcoaxial part (12, 3) mounted so as to move angularly with respect toeach other counter to elastic means (7) with circumferential action,said elastic means including elastic members (71, 72, 73) acting betweenradial lugs (55, 65) which are offset circumferentially and belonging totwo phasing washers (5, 6), said phasing washers being mounted so as torotate with respect to the first and second coaxial parts (12, 3),wherein said two phasing washers (5, 6) are mounted in the same plane,in reverse orientations and concentrically, one of the washers (6),referred to as the outer washer, surrounding the other washer (5),referred to as the inner washer, in that the lugs (55) of the innerwasher (5) are directed radially in a direction opposite to an axis ofthe first and second coaxial parts (12, 3), while the lugs (65) of theouter washer are directed radially towards the axis of the first andsecond coaxial parts (12, 3) and in that the inner washer (5) isrotatably mounted on said first coaxial part (3) of the torsion dampingdevice, while the outer washer (6) is rotatably mounted with respect toone of said first and second coaxial parts (3, 12) of the torsiondamping device.
 2. A torsion damping device according to claim 1,wherein the outer phasing washer (6) is rotatably mounted on the lugs(55) of the inner washer (5).
 3. A torsion damping device according toclaim 1, wherein the inner washer (5) is rotatably mounted on the firstcoaxial part (3) of the coaxial parts of the torsion damping device,while the outer washer (6) is rotatably mounted on lugs (95), said lugsbeing mounted to said second coaxial part (12) of the torsion dampingdevice.
 4. A torsion damping device according to claim 1, wherein saidsecond coaxial part (12) of the coaxial parts of the torsion dampingdevice has lugs (95) for supporting the elastic members (73), while thefirst coaxial part (3) of the torsion damping device has fingers (85),and the lugs (95) of the second coaxial part (12) are cut out for thepassage of said fingers (85).
 5. A torsion damping device according toclaim 4, wherein at least some the elastic members bear on the lugs (95)of the second coaxial part (12) of the coaxial parts of the torsiondamping device through support dishes (96) which have a rounded partinto which one of said fingers (85) is able to enter.
 6. A torsiondamping device according to claim 1, wherein said first coaxial part (3)has, from place to place, radial projections (9), while the inner washer(5) has local passages (51) into which the projections (9) are able toenter, so that the mounting of the inner washer (5) on the first coaxialpart (3) of the torsion damping device is of the bayonet type.
 7. Atorsion damping device according to claim 6, wherein the projections (9)are transversely wedge-shaped and have an inclined bearing face (36)opposite another inclined face (34) formed on said first coaxial part(3), so that there is formed locally a trapezoidal-shaped groove forhousing the inner washer (5).
 8. A hydrokinetic coupling apparatushaving a housing; a turbine wheel (14); and a locking clutch (10) actingbetween the housing and said turbine wheel, wherein said couplingapparatus further comprises a torsion damping device comprising: a firstand a second coaxial part (12, 3) mounted so as to move angularly withrespect to each other counter to elastic means (7) with circumferentialaction, said elastic means including elastic members (71, 72, 73) actingbetween radial lugs (55, 65) which are offset circumferentially andbelonging to two phasing washers (5, 6), said phasing washers beingmounted so as to rotate with respect to the first and second coaxialparts (12, 3), wherein said two phasing washers (5, 6) are mounted inthe same plane, in reverse orientations and concentrically, one of thewashers (6), referred to as the outer washer, surrounding the otherwasher (5), referred to as the inner washer, in that the lugs (55) ofthe inner washer (5) are directed radially in a direction opposite to anaxis of the first and second coaxial parts (12, 3), while the lugs (65)of the outer washer are directed radially towards the axis of the firstand second coaxial parts (12, 3), and in that the inner washer (5) isrotatably mounted on said first coaxial part (3) of the torsion dampingdevice, while the outer washer (6) is rotatably mounted with respect toone of said first and second coaxial parts (3, 12) of the torsiondamping device.
 9. A hydrokinetic coupling apparatus according to claim8, wherein the first coaxial part (3) of the torsion damping device is amass rotatably mounted on a tubular nose (17), said tubular nose beingfixed to the housing (12), and said housing constituting the secondcoaxial part (12) of the torsion damping device.
 10. A hydrokineticcoupling apparatus according to claim 9, wherein the mass has atransversely oriented annular projection (31) offering a contact surface(32) to a piston (2) of the locking clutch disposed at an outerperiphery of said mass.